205666231 has 4 divisors (see below), whose sum is σ = 212758200. Its totient is φ = 198574264.

The previous prime is 205666229. The next prime is 205666259. The reversal of 205666231 is 132666502.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 132666502 = 2 ⋅66333251.

It is a cyclic number.

It is not a de Polignac number, because 205666231 - 2¹ = 205666229 is a prime.

It is a super-2 number, since 2×205666231² = 84597197147490722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 205666193 and 205666202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205666261) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3545941 + ... + 3545998.

It is an arithmetic number, because the mean of its divisors is an integer number (53189550).

Almost surely, 2^205666231 is an apocalyptic number.

205666231 is a deficient number, since it is larger than the sum of its proper divisors (7091969).

205666231 is an equidigital number, since it uses as much as digits as its factorization.

205666231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7091968.

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 205666231 is about 14341.0679867296. The cubic root of 205666231 is about 590.2749183209.

The spelling of 205666231 in words is "two hundred five million, six hundred sixty-six thousand, two hundred thirty-one".